<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            display: flex;
        }

        .container div {
            height: 100px;
            /* flex: 1; */
            flex: 1 1 0;
        }

        .container div:nth-child(1) {
            background-color: red;
        }

        .container div:nth-child(2) {
            background-color: green;
        }

        .container div:nth-child(3) {
            background-color: blue;
        }
    </style>
</head>

<body>
    <div class="container">
        <div>1</div>
        <div>222222222</div>
        <div>33333333333333333333</div>
    </div>
</body>

</html>